1st, we had indoor cats from L.A.
Then, we had many, many rescues, and they were indoor-outdoor.
Then, I had indoor only again.
Finally, my ferals, which, by and large, wouldn't become 100% indoor cats, and still aren't, though they are in a lot more these days.
Now, I have Henry who is indoor only.
What I've learned, is that indoor only cats are a bit of a pain, and scary situations tend to arise now and then.
You have to work all the time at them not getting out, meaning no leaving a door open to take things in and out when cleaning.
And, if they get out, as you just experienced, it's not always easy to get them back in.
Sometimes they even run off, rather than staying in the yard, putting them in danger from dogs, cars, etc.
Apple Blossom, our little Siamese from L.A. had never been outdoors since we'd had her. One day, about 3 years into us moving here, she got out. She probably slipped out with one of the kids. She took off, and was never seen again. :-( We'd had her for about 5 years.
One plan that I have with Henry, is to put him into his figure-8 harness (he still doesn't fit quite yet into his xs one.), and take him out of the least used door on it. Letting him sniff the outside, and get used to walking around out there without running off.
I want to use a high end treat to draw his attention to me, rather than the outside too much, and want to put a bowl of food on the outdoor kitchen porch. That way he'll think about food being out there, and might go there instead of running. That will allow us to food call him, too.
It's a problem with indoor only cats...
I'm sorry that you got worn out, and that he was gone so long, but am glad that he didn't go far, and that you caught him! Whew!
Btw, am finally caught up with everything after all of my computer problems. Sent photos, and posted on I Can.
Love All Life; Thank You For Posting! :)